Wound healing, or wound repair, is the body's natural process of regenerating dermal and epidermal tissue. The processes of wound healing are complex and fragile. Among these, the treatment of full-thickness burns continues to be one of the most challenging tasks in medicine. Patients sustaining full thickness injuries over a large percentage body surface area (BSA) often incur complications from eschars, which may lead to systemic bacterial infection, hypovolemia, hypothermia, hypoperfusion, and hemoglobinuria due to rhabdomyolysis and hemolysis. Currently, full thickness burn wounds are generally healed with minimal cicatrization by autologous skin grafting. Autologous skin grafting has limitations, however: Patients incurring full thickness burn wounds over 20% BSA are limited to either temporary stretched meshed allografts from cadavers or artificial dermal regeneration templates such as porcine xenografts and collagen coated semi-permeable synthetic membranes. Along with being immunologically incompatible with the patient, these substitutes induce healing with an acute distribution of wide irregular collagen bands resulting in an uneven grid-like surface and excessive hyperplastic, hypertrophic scarring.
Various synthetic and natural polymers may be used to develop wound dressing materials, for example, hydrolytically unstable synthetic aliphatic polyesters such as poly(glycolic acid) (PGA), poly(L-lactic acid) (PLA) or natural-origin polymer such as chitosan. These polymers may suffer from side reactions or reduced performance, however, when subjected to the specific wound environment. For example, the acidity of the hydrolyzed bi-products of PGA or PLA polymers may inhibit full-thickness wound healing cascades; when immersed in an acidic wound environment, chitosan becomes soluble due to amine group protonation which can result in premature loss of mechanical integrity.
Hence, there is a need for new types of biomaterials that not only have improved biodegradability, biocompatibility and possess the wound healing properties of natural skin, but also have improved physical and mechanical properties, and satisfactory flexibility suitable for an effective wound dressing.